Automobile shock absorbing structure and automobile frame

Abstract

This automobile impact absorption structure comprises a first member and a second member, the first member having a flange portion, a side wall portion, and a top plate portion, the first member having continuously formed bead portions each having a flange bead extending in a direction intersecting the axial direction so as to divide the flange portion in the axial direction, and a side wall bead extending in a direction intersecting the axial direction so as to divide the side wall portion in the axial direction, the flange bead being formed to protrude in a direction away from the top plate portion of the first member, and the side wall bead being formed to protrude from the side wall portion towards the inside of the hollow cross section.

Description

[Technical Field]

[0001] The present invention relates to an automobile shock absorbing structure and an automobile frame. This application claims priority based on Japanese Patent Application No. 2024-059650, filed April 2, 2024, the contents of which are incorporated herein by reference. [Background technology]

[0002] In recent years, in order to combat global warming, automobiles are being required to reduce CO2 emissions, while collision safety regulations are becoming stricter. This has led to demands for lighter weight and improved collision safety in automobile components, making material selection and structural design crucial. Among automotive components, front side members, rear side members, crash boxes, and other components to which loads are input in the longitudinal direction (axial direction) of the component are required to absorb collision energy by bending deformation or by bellows deformation along the axial direction.

[0003] For example, Patent Document 1 discloses an automobile body structure consisting of side members and cross members, in which a crushable deformation portion is provided in the side member and a deformation-allowing portion is provided in a reinforcing member, and the cross section of the deformation-allowing portion is set so that the deformation stroke of the deformation-allowing portion approximately matches the crushing stroke of the crushable deformation portion based on the crushing stroke of the crushable deformation portion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-348824 Summary of the Invention [Problem to be solved by the invention]

[0005] According to the technology of Patent Document 1, the crushing stroke of the crushable deformation portion and the deformation stroke of the deformable portion match, which is said to ensure that the side member is crushed into a bellows-like shape. However, the technology of Patent Document 1 is premised on a structure in which a cross member is connected to the lower end of the side member via a reinforcing member, and it is necessary to consider not only the crushable deformation portion provided in the side member but also the cross section of the deformable portion provided in the reinforcing member. Therefore, further ingenuity is required to increase the amount of energy absorbed per member weight (energy absorption efficiency).

[0006] Therefore, an object of the present invention is to provide an energy absorbing structure and an automobile frame that can realize stable bellows deformation by the simple method of providing beads and exhibit excellent energy absorption efficiency. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention proposes the following means. (1) A first aspect of the present invention is an impact absorbing structure for an automobile, comprising a first member and a second member extending in an axial direction and joined to each other to form a hollow cross section, the first member comprising a flange portion, a side wall portion extending via a first ridge line formed on an edge of the flange portion, and a top plate portion extending via a second ridge line formed on an edge of the side wall portion opposite to the first ridge line, the first member having continuously formed bead portions including a flange bead extending in a direction intersecting the axial direction so as to divide the flange portion in the axial direction, and a side wall bead extending in a direction intersecting the axial direction so as to divide the side wall portion in the axial direction, the flange bead being formed to protrude in a direction away from the top plate portion of the first member, and the side wall bead being formed to protrude from the side wall portion toward the inside of the hollow cross section. The first member is a hat-shaped cross-section member having a pair of the flange portions and a pair of the side wall portions. do. (2) In the automobile impact absorbing structure described in (1) above, the second member may be formed with a bead portion that comes into surface contact with at least a portion of the flange bead of the bead portion of the first member. (3) In the shock absorbing structure for an automobile described in (1) or (2) above, the bottom of the flange bead of the first member may be flat. (4) In the automobile impact absorption structure described in (1) or (2) above, the bottom of the flange bead of the first member may be flat, and the bottom may be joined to the second member. (5) In the shock absorbing structure for an automobile described in (1) or (2) above, the bottom of the flange bead of the first member may be joined to the second member. (6) In the automobile impact absorption structure described in any one of (1) to (5) above, the second member may include a flange portion, a side wall portion extending via a third ridge line formed on an edge of the flange portion, and a top plate portion extending via a fourth ridge line formed on an edge of the side wall portion opposite the third ridge line. (7) In the shock absorbing structure for an automobile described in (6) above, a height H2 of the side wall portion of the second member may be smaller than a height H1 of the side wall portion of the first member. ( 8 )the above( 1 In the automobile impact absorption structure described in (1), the side wall beads may be formed on each of the pair of side wall portions, and the side wall beads formed on each of the pair of side wall portions may be formed at the same position in the axial direction. ( 9 )the above Any one of (1) to (8) In the automobile impact absorption structure described above, the side wall beads may be formed on each of the pair of side wall portions, and the side wall beads formed on each of the pair of side wall portions may have different depths. ( 10 ) above (1) ~ ( 9 In the shock absorbing structure for an automobile described in any one of the above, the length of the hollow cross section in a width direction, which is a direction perpendicular to the axial direction and parallel to the top plate portion of the first member, may be greater than the length in a height direction, which is perpendicular to the width direction and the axial direction. ( 11 ) above (1) ~ ( 10In the shock absorbing structure for an automobile described in any one of the above items (1) to (5), the first member may be made of a metal material. ( 12 The second aspect of the present invention is the above (1) to ( 11 ) is applied to a pair of tubular parts, and the pair of tubular parts is an automobile frame in which the side wall portions are formed on surfaces facing each other. ( 13 In the automobile impact absorbing structure described in (2) above, the bead portion of the second member may be formed at one location on each end of the second member in the width direction. [Effects of the Invention]

[0008] According to the above aspect of the present invention, the highly rigid first ridgeline is divided by the bead portion, thereby reducing the deformation resistance on the flange side when subjected to an axial compressive load (rigidity reduction effect). Furthermore, the ridgeline between the flange bead and the sidewall bead (bead portion first ridgeline) is located farther from the top plate portion of the first member (toward the second member) than the first ridgeline. Therefore, the space near the bead portion first ridgeline functions as a material inflow space during bellows deformation, preventing mutual interference between deformed portions within the bead (interference avoidance effect). Therefore, when an axial compressive load is applied to the shock absorbing structure, bellows deformation in the axial collapse mode can be realized more stably. As a result, stable bellows deformation can be realized by the simple technique of providing beads, and excellent energy absorption efficiency can be demonstrated. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view of a shock absorbing structure according to an embodiment of the present invention; [Figure 2] FIG. 2 is a cross-sectional end view taken along the cross-sectional line II in FIG. [Figure 3] FIG. 4 is a cross-sectional view of a portion of the first member where a bead portion is formed. [Figure 4]FIG. 4 is a cross-sectional view of a portion of the second member where a bead portion is formed. [Figure 5] FIG. 2 is an enlarged view of part A in FIG. [Figure 6] 6 is a cross-sectional end view taken along the cross-sectional line II-II in FIG. 5. [Figure 7] 1 is a plan view of a structure to which a shock absorbing structure according to an embodiment of the present invention is applied. [Figure 8] FIG. 10 is a cross-sectional view of a portion where a bead portion is formed in the impact absorbing structure according to the first modified example. [Figure 9] FIG. 10 is a cross-sectional view of a second member in the shock absorbing structure according to the first modified example. [Figure 10] FIG. 10 is a cross-sectional view of a portion where a bead portion is formed in a shock absorbing structure according to a second modified example. [Figure 11] FIG. 10 is a cross-sectional view of a first member in a shock absorbing structure according to a second modified example. [Figure 12] FIG. 10 is a cross-sectional view of a second member in a shock absorbing structure according to a second modified example. [Figure 13] FIG. 11 is a cross-sectional view of a portion where a bead portion is formed in a shock absorbing structure according to a third modified example. [Figure 14] FIG. 10 is a cross-sectional view of a portion where a bead portion is formed in a shock absorbing structure according to a fourth modified example. [Figure 15] FIG. 11 is a cross-sectional view of a portion where a bead portion is formed in a shock absorbing structure according to a fifth modified example. [Figure 16] FIG. 10 is a perspective view showing deformation of the shock absorbing structure according to Comparative Example 1. [Figure 17] FIG. 10 is a perspective view showing deformation of the shock absorbing structure according to Comparative Example 2. [Figure 18] 10 is a perspective view showing deformation of the shock absorbing structure according to the example of the present invention. FIG. [Figure 19] 1 is a graph showing the relationship between the crush amount (mm) and the energy absorption efficiency (kJ / kg) for Comparative Example 1, Comparative Example 2, and an example of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a shock absorbing structure for an automobile according to one embodiment of the present invention (hereinafter referred to as the shock absorbing structure according to this embodiment) will be described with reference to the drawings. Furthermore, since the impact absorption structure of this embodiment aims to absorb collision energy by bellows deformation in axial collapse mode, it is applied to the automobile frame in a position where the central axis of the impact absorption structure is approximately aligned with the fore-and-aft directions (forward and backward directions) of the automobile.

[0011] In this specification, the direction parallel to the central axis of the impact absorbing structure is referred to as the axial direction x, any one of the directions perpendicular to the axial direction x (for example, a direction that coincides with the vehicle height direction) is referred to as the height direction z, and of the directions perpendicular to the axial direction x, the direction perpendicular to the height direction z (for example, a direction that coincides with the vehicle width direction, or a direction parallel to the top plate portion of the first member described later when viewed in the axial direction) is referred to as the width direction y. For ease of explanation, the height direction z and width direction y correspond to the height direction z and width direction y of the vehicle, but for example, the height direction z may correspond to the left-right direction of the vehicle, and the width direction y may correspond to the up-down direction of the vehicle.

[0012] (Automobile Impact Absorption Structure 1) FIG. 1 is a perspective view of a shock absorbing structure 1 according to one embodiment of the present invention. 1, the shock absorbing structure 1 according to this embodiment has a hollow tubular shape extending in the axial direction x. The shock absorbing structure 1 is configured by spot welding a first member 10 having a bead portion 110 formed therein and a second member 20 having a bead portion 210 formed therein at joints P1 and P2.

[0013] FIG. 2 is an end view of a cross section taken along the cross section line II in FIG. 1, and shows a cross section perpendicular to the axial direction x of the region where the bead portion 110 and the bead portion 210 are formed in the shock absorbing structure 1. 2, the shock absorbing structure 1 is configured to have a substantially rectangular hollow cross section by joining together a first member 10, which is a hat-shaped cross section member, and a second member 20, which is a flat plate-shaped cross section member. Note that other members such as reinforcements may be attached inside the hollow cross section of the shock absorbing structure 1.

[0014] (First member 10) Fig. 3 is a cross-sectional view of a portion where the bead portion 110 is formed in the first member 10. More specifically, Fig. 3 is a view of a cross section of the portion perpendicular to the axial direction x as viewed from the axial direction x. As shown in FIG. 3, the first member 10 has a pair of flange portions 11, a pair of side wall portions 13, and a top plate portion 15. The flange portion 11 and the side wall portion 13 are connected across a first ridge line L1a extending in the axial direction x, and the side wall portion 13 and the top plate portion 15 are connected across a second ridge line L2a extending in the axial direction x. That is, the first member 10 comprises a flange portion 11, a side wall portion 13 extending via a first ridge line L1a formed on the edge of the flange portion 11, and a top plate portion 15 extending via a second ridge line L2a formed on the edge of the side wall portion 13 opposite the first ridge line L1a.

[0015] (Second member 20) Fig. 4 is a cross-sectional view of a portion where the bead portion 210 is formed in the second member 20. More specifically, Fig. 4 is a view of a cross section of the portion perpendicular to the axial direction x as viewed from the axial direction x. As shown in Fig. 4, the second member 20 has a flat portion 21. As shown in Fig. 1, a surface of the flat portion 21 near an edge in the width direction y is overlapped with the flange portion 11 of the first member 10 and spot-welded to it at a joint P1.

[0016] The first member 10 (and the second member 20) are preferably made of a metal material and can be obtained, for example, by forming a steel plate (blank) by cold pressing or hot stamping. The thickness of the steel plate (blank) may be 0.3 mm or more and 2.3 mm or less. The hot stamping method is a method of heating a blank, forming the heated blank in a forming die, and then rapidly cooling the blank in the die to give the blank a desired shape and strength. The heating temperature of the blank should be the Ac3 point or higher. The Ac3 point is the temperature at which ferrite disappears in the metal structure of the blank. The metal structure after processing by the hot stamping method becomes a structure mainly composed of martensite.

[0017] (Bracket 50) 1, a flat bracket 50 is attached to the ends of the first member 10 and the second member 20 in the axial direction x. The impact absorbing structure 1 according to this embodiment is connected to a bumper 60 (not shown in FIG. 1) via this bracket 50.

[0018] (Bead portion 110 of first member 10) 3, the bead portion 110 of the first member 10 is continuously formed so as to divide the flange portion 11, the first ridge line L1a, the side wall portion 13, and the second ridge line L2a in the axial direction x. As shown in Fig. 3, the bead portion 110 is not formed in the central portion of the top plate portion 15 in the width direction y. In the shock absorbing structure 1 according to this embodiment, one bead portion 110 is formed on each side of the first member 10 in the width direction y. The bead portions 110 on both sides are formed at the same position in the axial direction x, that is, facing each other. This makes it possible to more stably achieve bellows deformation in the collapse mode. However, the bead portion 110 may be formed on only one of both sides in the width direction y of the first member 10. Furthermore, the bead portions 110 on both sides may be formed at different positions in the axial direction x.

[0019] (Bead part 110) Fig. 5 is an enlarged view of part A in Fig. 1. As shown in Fig. 5, the bead portion 110 has a flange bead 111 extending in a direction intersecting the axial direction x so as to divide the flange portion 11 in the axial direction x, and a side wall bead 113 extending in a direction intersecting the axial direction x so as to divide the side wall portion 13 in the axial direction x. As shown in FIGS. 1 and 5, a bead portion first ridge line L1b exists between the flange bead 111 and the side wall bead 113. As shown in FIG. 1, a bead portion second ridge line L2b exists between the side wall bead 113 and the top plate portion 15. As shown in FIG.

[0020] As shown in FIG. 5, the flange bead 111 of the bead portion 110 has a groove shape that is made up of a bottom portion 111a and a pair of wall portions 111b that are connected to the end edges of the bottom portion 111a in the axial direction x. Similarly, the side wall bead 113 of the bead portion 110 has a groove shape that is constituted by a bottom portion 113a and a pair of wall portions 113b that are connected to the end edges of the bottom portion 113a in the axial direction x.

[0021] (Rigidity reduction effect) Typically, in hollow tubular members constructed by joining multiple components with flanges, the multiple components overlap at the flanges, and ridges extend axially near the flanges. Therefore, in a cross section perpendicular to the axial direction of the hollow tubular member, the flange side experiences greater deformation resistance when subjected to an axial compressive load than the side opposite the flange (the top plate in the case of a hat-shaped cross-section member). Therefore, in order to achieve stable energy absorption, it was necessary to adopt a complex structure that induces a bending deformation mode at multiple locations, which allows for relatively stable deformation mode control. On the other hand, according to the shock absorbing structure 1 of this embodiment, the bead portion 110 is formed not only on the side wall bead 113 but also continuously with the flange bead 111. Therefore, the first ridge line L1a, which has high rigidity, is divided by the bead portion 110. Therefore, it is possible to reduce the deformation resistance on the flange side when an axial compressive load is applied. Therefore, by using the simple technique of providing a bead, the difference in rigidity between the flange-side ridgeline and the top-plate-side ridgeline can be reduced, and high energy absorption can be achieved through stable bellows deformation.

[0022] Returning to Fig. 3, it is preferable that the width W1 in the width direction y of the hollow cross section of the shock absorbing structure 1 according to this embodiment is greater than the height H1 in the height direction z. More specifically, the width W1 is the distance in the width direction y between the pair of side wall portions 13 of the first member 10, and the height H1 is the distance in the height direction z between the flange portion 11 and the top plate portion 15 of the first member 10. As shown in Fig. 3, the width W1 and the height H1 are dimensions based on the center of the plate thickness of each portion. It is preferable that the width W1 of the hollow cross section is greater than the height H1, since this more reliably reduces the deformation resistance on the flange side when subjected to an axial compressive load.

[0023] (Interference avoidance effect) The flange bead 111 of the bead portion 110 is formed so as to protrude in a direction away from the top plate portion 15 of the first member 10 (i.e., convex in a direction away from the central axis). On the other hand, the side wall bead 113 connected to the flange bead 111 is formed so as to protrude from the side wall portion 13 toward the inside of the hollow cross section (i.e., toward the central axis). Therefore, the flange bead 111 and the side wall bead 113 form a groove that is bent in a substantially L-shape when viewed in the axial direction. Therefore, the bead portion first ridge line L1b is located at a position spaced apart from the first ridge line L1a not only in the width direction y but also in the height direction z. When the bead is formed only on the side wall, the ridge line of the part where the bead is formed (the ridge line between the flange and the side wall) is located at a position separated only in the width direction y from the ridge line of the part where the bead is not formed (the ridge line between the flange and the side wall). In this case, as the bellows-like deformation progresses, the deformed parts may interfere with each other within the bead, increasing the deformation resistance on the flange side. On the other hand, in the shock absorbing structure 1 according to this embodiment, the first ridge line L1b of the bead portion is located at a distance from the first ridge line L1a not only in the width direction y but also in the height direction z, so that the area near the first ridge line L1b of the bead portion functions as a material inflow space when the bellows-like deformation progresses, thereby preventing the deformed portions from interfering with each other within the bead (interference avoidance effect). Therefore, bellows deformation in the axial collapse mode can be achieved more stably.

[0024] (radius of curvature of ridge line) The radius of curvature Ra of the first ridge line L1a in the cross section perpendicular to the axial direction x may be 3 mm to 20 mm. The radius of curvature Rb of the first ridge line L1b of the bead portion in a cross section perpendicular to the axial direction x may be 3 mm to 100 mm. The radius of curvature Ra is the radius of curvature of the first ridge line L1a measured at a position 10 mm away in the axial direction x from the position where the bead portion 110 is formed. The radius of curvature Rb is the radius of curvature of the bead portion first ridge line L1b measured at the center position of the bead portion 110 in the axial direction x.

[0025] Here, in order to advantageously obtain the effect of reducing rigidity, it is preferable to satisfy the relationship Rb>Ra. Since the ridges extending in the axial direction contribute to high rigidity, it is preferable that the radius of curvature Ra is small for the first ridges L1a where no beads are formed, whereas it is preferable that the radius of curvature Rb is large for the first ridges L1b of the bead portion to reduce rigidity. Therefore, by satisfying the relationship Rb>Ra, it is possible to reduce the deformation resistance on the flange side (flange bead 111) when subjected to an axial compressive load while maintaining high rigidity in the areas where no bead is formed. Therefore, it is possible to more stably achieve bellows deformation in the axial crushing mode. The relationship Rb>Ra×1.05 may be satisfied, or the relationship Rb>Ra×1.10 may be satisfied.

[0026] On the one hand, in order to advantageously obtain the interference avoidance effect, it is preferable to satisfy the relationship of Rb < Ra. The smaller the radius of curvature of the first ridge line L1b of the bead portion, the more the first ridge line L1b of the bead portion can be positioned at a position further separated from the first ridge line L1a in the width direction y and the height direction z. Therefore, the above-mentioned material inflow space can be widely secured, and the interference avoidance effect can be enhanced. Incidentally, the first ridge line L1b of the bead portion can be formed using, for example, a press die provided with a protrusion having a shape corresponding to the bead shape. In that case, due to reasons related to press forming technology such as low shape freezing property during press forming, the radius of curvature Rb of the first ridge line L1b of the bead portion becomes larger than the radius of curvature Ra of the first ridge line L1a, and the separation distance of the first ridge line L1b of the bead portion in the width direction y and the height direction z with respect to the first ridge line L1a cannot be sufficiently secured, and the interference avoidance effect at the first ridge line L1b of the bead portion may not be sufficiently obtained. Therefore, when forming the bead portion 110, it is preferable to press-mold the first ridge line L1b of the bead portion to be more distal from the top plate portion 15. Only one first ridge line L1b of the bead portion is formed in one bead portion 110, but two or more may be formed.

[0027] (Shape of the bottom portion 111a of the bead portion 110) In the bead portion 110, the bottom portion 111a of the flange bead 111 and the bottom portion 113a of the side wall bead 113 are preferably flat. In this case, since the first ridge line L1b of the bead portion can be positioned at a position further separated from the first ridge line L1a in the width direction y and the height direction z, the above-mentioned interference avoidance effect can be enhanced. Furthermore, when a joint P2 for joining the flange bead 111 to the second member 20 is provided, the flat bottom 111a of the flange bead 111 can improve workability when joining to the second member 20 (specifically, the flat bottom 211a of the flange bead 211 described later). In particular, when the joint P2 for joining the flange bead 111 to the second member 20 is a joint formed by spot welding or laser welding, the flat shape can further improve workability during spot welding or laser welding. Here, "the bottom 111a of the flange bead 111 is flat" means that the radius of curvature in a cross section perpendicular to the axial direction x and height direction z at the center position of the flange bead 111 in the width direction y and axial direction x is 50 mm or more. Furthermore, "the bottom 113a of the side wall bead 113 is flat" means that the radius of curvature in a cross section perpendicular to the axial direction x and width direction y at the center position of the side wall bead 113 in the height direction z and axial direction x is 50 mm or more.

[0028] (Bead dimensions) The depth d of the bead portion 110 may be 3 mm or more. If the depth d is 3 mm or more, buckling can occur stably. From the viewpoint of workability, the depth d may be 20 mm or less. The depth d1 of the flange bead 111 is preferably larger than the radius of curvature Ra of the first ridge line L1a. In this case, the depth of the flange bead 111 is ensured, and the bead portion first ridge line L1b can be positioned sufficiently farther away from the first ridge line L1a in the width direction y and the height direction z, thereby further enhancing the above-mentioned interference avoidance effect.

[0029] When bead portions 110 are formed on both sides in the width direction, it is preferable that the depth d1 of the bead portions be different from each other. This is because, when the impact absorbing structure 1 according to this embodiment is applied to an automobile, deformation tends to occur in a manner that bends to either the left or right of the vehicle when an axial compressive load is applied. Designing the depths d1 of the bead portions 110 to be different from each other allows for stable bellows deformation.

[0030] (Bead portion 210 of second member 20) In the shock absorbing structure 1 according to this embodiment, the bead portion 210 of the second member 20 has a shape corresponding to the bead portion 110 of the first member . Figure 6 is an end view of a cross section taken along the cross-sectional line II-II in Figure 5, and shows a cross section perpendicular to the width direction y of the area where the bead portion 110 of the first member 10 and the bead portion 210 of the second member 20 are formed. As shown in FIGS. 5 and 6, the flange bead 111 of the bead portion 110 has a trapezoidal cross-sectional shape composed of a bottom portion 111a and a pair of wall portions 111b connected to the end edges of the bottom portion 111a in the axial direction x. Similarly, the flange bead 211 of the bead portion 210 of the second member 20 has a trapezoidal cross-sectional shape composed of a bottom portion 211a that overlaps the bottom portion 111a of the first member 10 and a pair of wall portions 211b that connect to the end edges of the bottom portion 211a in the axial direction x. According to this configuration, even if the first member 10 has the bead portion 110 that protrudes in the height direction z, at least a part of the bead portion 210 of the second member 20 can be in surface contact with at least a part of the flange bead 111 of the bead portion 110 of the first member 10. Therefore, the joining strength between the first member 10 and the second member 20 can be increased.

[0031] (Bead joint P2) Furthermore, in the shock absorbing structure 1 according to this embodiment, the first member 10 is joined to the second member 20 not only at the joint P1 of the flange portion 11 but also at the joint P2 of the bead portion 110. This further increases the joining strength between the first member 10 and the second member 20, which is preferable because it makes it easier for the second member 20 to follow the deformation of the first member 10. Even in a configuration in which the joint portion P2 is not provided in the bead portion 110, the bottom portion 111a of the bead portion 110 of the first member 10 is disposed opposite the bottom portion 211a of the bead portion 210 of the second member 20, and therefore, during impact absorption, the bottom portion 111a of the bead portion 110 of the first member 10 deforms toward the bottom portion 211a of the bead portion 210 of the second member 20. Therefore, this is preferable in that the effect of making the second member 20 follow the deformation of the first member 10 can be easily obtained.

[0032] 7 is a plan view of an automobile frame 1000 having a pair of tubular portions 1001 to which the shock absorbing structure 1 according to this embodiment is applied. In this automobile frame 1000, each end of the pair of tubular portions 1001 is connected to a bumper 60 via a bracket 50. As shown in Figure 7, when the shock absorbing structure 1 is applied to a pair of parallel tubular portions 1001, side wall portions 13 on which side wall beads 113 of the first members 10 of each shock absorbing structure 1 are formed are arranged on the opposing surfaces of the pair of shock absorbing structures 1 and on the opposite surface thereof. Here, when the tubular portions 1001 receive a load input from the bumper 60, the load in the axial direction x tends to be biased toward the outside in the width direction y. Therefore, stress is less likely to concentrate on the inside (the surfaces facing each other) of the pair of tubular portions 1001 than on the outside. Therefore, a configuration may be adopted in which the side wall portions 13 on which the side wall beads 113 of the first members 10 of each impact absorbing structure 1 are formed are disposed only on the surfaces facing each other. It is also preferable that the depth of the beads 110 formed on the side wall portions 13 on the opposing surfaces is greater than the depth of the beads 110 formed on the side wall portions 13 on the opposite surfaces. The shape of the bracket 50 is preferably designed so that the direction of load input to the impact absorption structure 1 during a collision coincides with the axial direction x of the impact absorption structure 1. This prevents the first member 10 and the second member 20 from spreading outward relative to each other when subjected to an axial compressive load, making it possible to increase energy absorption efficiency.

[0033] (Variation) Although the present invention has been described above based on the present embodiment, it should not be construed as being limited to this. For example, the following modified examples can be applied. Note that the same reference numerals are used for components that are substantially the same as those described in the shock absorbing structure 1 according to the above embodiment, and duplicated descriptions will be omitted.

[0034] (First Modification) FIG. 8 shows a shock absorbing structure 1A according to a first modified example. In the shock absorbing structure 1 according to the above embodiment, the second member 20 is a flat cross-section member that does not have a side wall portion, but the shock absorbing structure 1A shown in FIG. 8 uses a second member 20A that is a hat-shaped cross-section member.

[0035] (Second member 20A) FIG. 9 is a cross-sectional view of the portion of the second member 20A where the bead portion 210A is formed, the cross-section being perpendicular to the axial direction x, as viewed from the axial direction x. As shown in FIG. 9, the second member 20A is a hat-shaped cross-section member having a pair of flange portions 21A, a pair of side wall portions 23A, and a top plate portion 25A. The flange portion 21A and the side wall portion 23A are connected across a third ridge line L3a extending in the axial direction x. The side wall portion 23A and the top plate portion 25A are connected across a fourth ridge line L4a extending in the axial direction x. The second member 20A has a bead portion 210A formed thereon, the bead portion 210A having a shape corresponding to the bead portion 110 of the first member 10.

[0036] (Bead part 210A) The bead portion 210A of the second member 20A is formed continuously from the outer end of the flange portion 21A to the bead portion third ridge line L3b. The bead portion 210A is formed in a convex shape in the same direction as the protruding direction of the bead portion 110 of the first member 10. The bead portion 210A is formed continuously from the outer end of the flange portion 21A to the bead portion third ridge line L3b, but may also be formed continuously on the side wall portion 23A to the bead portion fourth ridge line L4a.

[0037] In this first modified example, the flange portion 21A of the second member 20A is joined (for example, by spot welding) to the flange portion 11 of the first member 10, thereby joining the first member 10 and the second member 20A to each other. According to this configuration, the flange can be positioned closer to the central axis than in the shock absorbing structure 1 according to the above-described embodiment, and superior energy absorption efficiency can be achieved.

[0038] In this first modified example, it is preferable that height H1 of first member 10 is greater than height H2 of second member 20A (H1>H2). As described in FIG. 3, height H1 is the distance in the height direction z between flange portion 11 and top plate portion 15 of first member 10. As shown in FIG. 9, height H2 is the distance in the height direction z between flange portion 21A and top plate portion 25A of second member 20A. As shown in FIGS. 3 and 9, heights H1 and H2 are dimensions based on the center of the plate thickness of each portion. When an axial compressive load is applied, deformation of the first member 10 occurs starting from the side wall bead 113, and deformation of the second member 20A follows this deformation. If the height H2 of the second member 20A is equal to or greater than the height H1, the deformation resistance of the second member 20A increases, making it difficult for bellows deformation to occur. Therefore, a configuration in which H1 > H2 allows stable bellows deformation to be achieved, thereby achieving better energy absorption efficiency.

[0039] (Second Modification) FIG. 10 shows a shock absorbing structure 1B according to a second modified example. In the shock absorbing structure 1 according to the present embodiment described above, the first member 10 is a hat-shaped cross-section member having a pair of flange portions 11. On the other hand, in the shock absorbing structure 1B according to the second modified example, the first member 10B has a flange portion 11B on only one side.

[0040] (First member 10B) As shown in FIG. 10, the shock absorbing structure 1B is configured such that a first member 10B and a second member 20B are joined together to form a substantially rectangular hollow cross section.

[0041] FIG. 11 is a diagram showing a cross section perpendicular to the axial direction x of the portion of the first member 10B where the bead portion 110B is formed, as viewed from the axial direction x. As shown in Figure 11, the first member 10B has a flange portion 11B, a first side wall portion 13-1B connected to the flange portion 11B across a first ridge line L1a, a top plate portion 15B connected to the first side wall portion 13-1B across a second ridge line L2a, and a second side wall portion 13-2B connected to the top plate portion 15B across another second ridge line L2a.

[0042] (Bead portion 110B) The bead portion 110B has substantially the same configuration as the bead portion 110 of the shock absorbing structure 1 according to the above-described embodiment, and has a flange bead 111B extending in a direction intersecting the axial direction x so as to divide the flange portion 11B in the axial direction x, and a side wall bead 113B extending in a direction intersecting the axial direction x so as to divide the first side wall portion 13-1B in the axial direction x. As shown in FIG. 11, a bead portion first ridge line L1b exists between the flange bead 111B and the side wall bead 113B. As shown in FIG. 11, a bead portion second ridge line L2b exists between the side wall bead 113B and the top plate portion 15B.

[0043] In the example shown in FIG. 11, no side wall bead is formed on the second side wall portion 13-2B facing the first side wall portion 13-1B, but a side wall bead may also be formed on the second side wall portion 13-2B.

[0044] (Second member 20B) FIG. 12 is a cross-sectional view of the portion of the second member 20B where the bead portion 210B is formed, taken along a line perpendicular to the axial direction x, as viewed from the axial direction x. As shown in FIG. 12, the second member 20B has a flat portion 21B and a side wall portion 23B that is connected to the flat portion 21B via a third ridge line L3a.

[0045] (Bead portion 210B) The bead portion 210B of the second member 20B is formed in a convex shape in the same direction as the protruding direction of the flange bead 111B of the first member 10B.

[0046] According to the configurations of the first and second modified examples, similar to the shock absorbing structure 1 according to the above-described embodiment, a stable bellows-like deformation can be achieved due to the effect of reducing rigidity and the effect of avoiding interference, thereby making it possible to improve the energy absorption efficiency.

[0047] Moreover, various modifications can be applied to the bead portion 110 of the first member 10. Hereinafter, the modifications will be described with reference to FIGS.

[0048] (Third Modification) In the shock absorbing structure 1C which is a third modified example of the shock absorbing structure, a notch Q is formed in the flange portion 21C of the second member 20C. The first member 10 has the same configuration as the first member 10 of the shock absorbing structure 1 according to this embodiment described above.

[0049] Fig. 13 is a cross-sectional view of the bead portion 110 of the first member 10. More specifically, Fig. 13 is a cross-section perpendicular to the width direction y at a location where the flange bead 111 is formed. In this third modified example, a notch Q is formed in the second member 20C at a portion corresponding to the bead portion 110 of the first member 10. That is, the second member 20C does not have a portion corresponding to the bead portion 210 formed in the second member 20 of the shock absorbing structure 1 as shown in Figs. In this configuration, the bottom 111a of the flange bead 111 of the first member 10 is not joined to the second member 20C, and the flange portion 11 of the first member 10 is joined to the flange portion 21C of the second member 20, thereby joining the first member 10 and the second member 20C. The flange bead 111 of the first member 10 may be joined to the flange portion 21C of the second member 20C by arc welding.

[0050] (Fourth Modification) In the shock absorbing structure 1D which is a fourth modified example of the shock absorbing structure, a first member 10D has a bead portion 110D having an arc-shaped cross section. Fig. 14 is a cross-sectional view of the bead portion 110D of the first member 10D. More specifically, Fig. 14 is a cross-section perpendicular to the width direction y at the location where the flange bead 111D is formed. In this fourth modified example, the flange bead 111D has an arc-shaped cross section formed by a bottom portion 111aD and a pair of wall portions 111bD. In this configuration, a bottom portion 111aD of a flange bead 111D of a first member 10D may be joined to a second member 20D having a bead portion 210D with an arc-shaped cross section.

[0051] (Fifth Modification) In an impact absorbing structure 1E which is a fifth modified example of the impact absorbing structure, a first member 10E has a bead portion 110E with a triangular cross section. Fig. 15 is a cross-sectional view of the bead portion 110E. More specifically, Fig. 15 is a cross-section perpendicular to the width direction y at the location where the flange bead 111E is formed. In the fifth modified example, the flange bead 111E has a triangular cross-sectional shape formed by a bottom portion 111aE and a pair of wall portions 111bE. In this configuration, the bottom portion 111aE of the flange bead 111E of the first member 10E may be joined to a second member 20E having a bead portion 210E with a triangular cross-sectional shape.

[0052] (Other variations) The shock absorbing structures 1A to 1E according to the above-described modifications can achieve the same effects as the shock absorbing structure according to the embodiment. As other modifications, the following configurations are possible. For example, the bead portion 110 of the first member 10 and the bead portion 210 of the second member 20 may be formed in plural and spaced apart from each other in the axial direction x. The bead portions 210 of the second member 20 are formed at one location on each end of the second member 20 in the width direction y, but may be formed linearly so as to connect both ends in the width direction y. Furthermore, a bead may be formed on the top plate portion 15 of the first member 10 so as to protrude outward (that is, so as to protrude in a direction away from the central axis). Furthermore, when the second member 20A, which is a hat-shaped cross-section member, is used as the second member as in the first modified example, a bead may be formed on the top plate portion 25 thereof so as to protrude outward (i.e., so as to protrude in a direction away from the central axis). The shock absorbing structure 1 is configured by joining the first member 10 and the second member 20 to each other by spot welding at joints P1 and P2, but instead of spot welding, they may be joined by laser welding, arc welding, or plasma welding. Also, the first member 10 and the second member 20 may be joined by mechanical fastening. Furthermore, the above joining modes may be combined.

[0053] (Example) As an experiment to confirm the effect of the present invention, hollow tubular members (length = 600 mm, width = 150 mm, height = 70 mm) obtained by press forming from the same type of steel plate material were prepared. One end of the specimen in the axial direction x was fixed, and an impactor was made to collide with the other end in the axial direction x at a speed of 80 km / h. A compressive load was applied in the axial direction x, and the amount of crushing in the axial direction x and the load were measured.

[0054] 16 is a perspective view showing deformation of the shock absorbing structure according to Comparative Example 1. In Comparative Example 1, a configuration was adopted in which no bead portion was provided on either the side wall or the flange. 17 is a perspective view showing deformation of the shock absorbing structure according to Comparative Example 2. Comparative Example 2 employs a configuration in which bead portions are provided only on the side walls (including the ridge lines of the top plate and side walls). Fig. 18 is a perspective view showing deformation of the shock absorbing structure according to an example of the invention. Example 1 of the invention is based on the configuration of the shock absorbing structure 1 according to the embodiment shown in Fig. 1. That is, bead portions are provided on the side walls and flanges.

[0055] FIG. 19 is a graph showing the relationship between the crush amount (mm) and the energy absorption efficiency (kJ / kg) for Comparative Example 1, Comparative Example 2, and an example of the invention. In the shock absorbing structure according to Comparative Example 1, since no bead portion was provided, the rigidity of the flange side was higher than the rigidity of the top plate side, and a deformation mode occurred in which the structure bent in a direction from the flange side toward the top plate side. Therefore, the shock absorbing structure according to Comparative Example 1 did not achieve desirable deformation by bellows deformation, and the energy absorption efficiency at the time when the collapse amount reached 200 mm was 2.1 kJ / kg.

[0056] In the impact absorbing structure of Comparative Example 2, by providing the bead portion only to the side wall (including the ridgeline of the top plate and side wall), bellows deformation was induced in the early stages of collapse, but as the bellows deformation progressed, the end of the side wall bead (the end near the ridgeline between the side wall and flange) was not deformed sufficiently, and a deformation mode occurred in which the bead bent in a direction from the flange side toward the top plate side. Therefore, the impact absorbing structure of Comparative Example 2 did not achieve desirable bellows deformation, and the energy absorption efficiency at the time when the collapsed amount reached 200 mm was 2.3 kJ / kg (110% of Comparative Example 1).

[0057] On the other hand, with the impact absorbing structure according to the example of the invention, by providing a bead on the flange so that the high-rigidity portion such as the flange-side ridgeline is removed from the side wall bead, a more stable bellows-like deformation can be achieved. Therefore, with the impact absorbing structure according to the example of the invention, the energy absorption efficiency at the time when the collapse amount reached 200 mm was 2.8 kJ / kg (133% of Comparative Example 1). [Industrial Applicability]

[0058] According to the present disclosure, an energy absorbing structure and an automobile frame are provided that realize stable bellows deformation by the simple method of providing beads and are capable of exhibiting excellent energy absorption efficiency. [Explanation of symbols]

[0059] 1. Shock absorbing structure 10 First member 11 Flange 13 Side wall 15 Top plate 110 Bead section 111 flange bead 111a bottom 111b Wall section 113 Sidewall bead 20 Second member 21 Flat area 210 Bead section 211 Flange bead 211a bottom 211b Wall section 50 bracket L1a first ridgeline L1b First ridge of bead L2a Second ridge L2b Second ridge of bead P1, P2 joint y width direction z Height direction x-axis direction

Claims

1. An automobile shock absorbing structure, a first member and a second member extending in an axial direction and joined to each other to form a hollow cross section; The first member is A flange portion, a sidewall portion extending along a first ridge line formed on an edge of the flange portion; a top plate portion extending via a second ridge line formed on an edge of the side wall portion opposite to the first ridge line; Equipped with The first member, a flange bead extending in a direction intersecting the axial direction so as to divide the flange portion in the axial direction; a side wall bead extending in a direction intersecting the axial direction so as to divide the side wall portion in the axial direction; A bead portion having the following structure is continuously formed: the flange bead is formed to protrude in a direction away from the top plate portion of the first member, and the side wall bead is formed to protrude from the side wall portion toward the inside of the hollow cross section, The first member is a hat-shaped cross-section member having a pair of the flange portions and a pair of the side wall portions. A shock absorbing structure for an automobile.

2. The second member has a bead portion that comes into surface contact with at least a part of the flange bead of the bead portion of the first member.

2. The shock absorbing structure for an automobile according to claim 1.

3. The bottom of the flange bead of the first member is flat.

2. The shock absorbing structure for an automobile according to claim 1.

4. The bottom of the flange bead of the first member is flat, and the bottom is joined to the second member.

2. The shock absorbing structure for an automobile according to claim 1.

5. The bottom of the flange bead of the first member is joined to the second member.

2. The shock absorbing structure for an automobile according to claim 1.

6. The second member is A flange portion, a side wall portion extending along a third ridge line formed on an edge of the flange portion; a top plate portion extending via a fourth ridge line formed on an edge of the side wall portion opposite to the third ridge line; Equipped with 2. The shock absorbing structure for an automobile according to claim 1.

7. The height H2 of the side wall portion of the second member is smaller than the height H1 of the side wall portion of the first member.

7. The shock absorbing structure for an automobile according to claim 6.

8. the side wall beads are formed on the pair of side wall portions, The side wall beads formed on the pair of side wall portions are formed at the same position in the axial direction.

2. The shock absorbing structure for an automobile according to claim 1.

9. the side wall beads are formed on the pair of side wall portions, The side wall beads formed on the pair of side wall portions have different depths.

2. The shock absorbing structure for an automobile according to claim 1.

10. The hollow cross section has a width direction perpendicular to the axial direction and parallel to the top plate portion of the first member that is longer than a height direction perpendicular to the width direction and the axial direction.

2. The shock absorbing structure for an automobile according to claim 1.

11. The first member is made of a metal material.

2. The shock absorbing structure for an automobile according to claim 1.

12. A vehicle having a pair of tubular portions to which the automobile shock absorbing structure according to any one of claims 1 to 11 is applied, The pair of tubular portions have the side wall portions formed on surfaces facing each other. A vehicle frame characterized by:

13. The bead portion of the second member is formed at each end in the width direction of the second member.

3. The shock absorbing structure for an automobile according to claim 2.

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